.role-selection {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  /* background: linear-gradient(to bottom, #1E90FF, #00BFFF);  /* 使用渐变背景 */
}

.role-options {
  display: flex;
  justify-content: space-evenly;  /* 使用 space-evenly 来确保按钮间隔一致 */
  width: 70%;  /* 控制按钮容器宽度 */
}

.role-btn {
  width: 120px;
  height: 120px;
  border-radius: 50%;  /* 让按钮变圆 */
  background-color: #4CAF50;
  color: white;
  font-size: 16px;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.2);
  transition: background-color 0.3s ease;
}

.role-btn:hover {
  background-color: #45a049;
}

.role-btn:active {
  background-color: #388e3c;  /* 按钮按下时颜色 */
}